<?php

/* vim: set expandtab shiftwidth=4 softtabstop=4 tabstop=4: */

/**
 * RC4Crypt 3.2
 *
 * RC4Crypt is a petite library that allows you to use RC4
 * encryption easily in PHP. It's OO and can produce outputs
 * in binary and hex.
 *
 * (C) Copyright 2006 Mukul Sabharwal [http://mjsabby.com]
 *     All Rights Reserved
 *
 * @link http://rc4crypt.devhome.org
 * @author Mukul Sabharwal <mjsabby@gmail.com>
 * @version $Id: class.rc4crypt.php,v 3.2 2006/03/10 05:47:24 mukul Exp $
 * @copyright Copyright &copy; 2006 Mukul Sabharwal
 * @license http://www.gnu.org/copyleft/gpl.html
 * @package RC4Crypt
 */

/**
 * RC4 Class
 * @package RC4Crypt
 */
class RC4Crypt {
	/**
	 * The symmetric encryption function
	 *
	 * @param string $pwd Key to encrypt with (can be binary of hex)
	 * @param string $data Content to be encrypted
	 * @param bool $ispwdHex Key passed is in hexadecimal or not
	 * @access public
	 * @return string
	 */
	public static function encrypt ($pwd, $data, $ispwdHex = 0)
	{
		if ($ispwdHex)
		$pwd = @pack('H*', $pwd); // valid input, please!

		$key[] = '';
		$box[] = '';
		$cipher = '';

		$pwd_length = strlen($pwd);
		$data_length = strlen($data);

		for ($i = 0; $i < 256; $i++)
		{
			$key[$i] = ord($pwd[$i % $pwd_length]);
			$box[$i] = $i;
		}
		for ($j = $i = 0; $i < 256; $i++)
		{
			$j = ($j + $box[$i] + $key[$i]) % 256;
			$tmp = $box[$i];
			$box[$i] = $box[$j];
			$box[$j] = $tmp;
		}
		for ($a = $j = $i = 0; $i < $data_length; $i++)
		{
			$a = ($a + 1) % 256;
			$j = ($j + $box[$a]) % 256;
			$tmp = $box[$a];
			$box[$a] = $box[$j];
			$box[$j] = $tmp;
			$k = $box[(($box[$a] + $box[$j]) % 256)];
			$cipher .= chr(ord($data[$i]) ^ $k);
		}
		return $cipher;
	}
	/**
	 * Decryption, recall encryption
	 *
	 * @param string $pwd Key to decrypt with (can be binary of hex)
	 * @param string $data Content to be decrypted
	 * @param bool $ispwdHex Key passed is in hexadecimal or not
	 * @access public
	 * @return string
	 */
	public static function decrypt ($pwd, $data, $ispwdHex = 0)
	{
		return RC4Crypt::encrypt($pwd, $data, $ispwdHex);
	}
}
?>
